Abstract

Pedestrians suffer significant injuries from ground contact, but attempts to reduce them have been limited. A recent study using multi-body simulations showed ground contact injury may be improved by controlling vehicle braking. The aim of the study is to assesses whether controlled braking would be beneficial in real-world collisions. PC-Crash was used to reconstruct 150 freely available real-world vehicle pedestrian video collisions. Pairwise comparison of actual versus controlled braking was then performed for each case. Pedestrian injury evaluation metrics included head injury criterion HIC15 and pelvis contact force, and another metric named separation distance between the vehicle and pedestrian at the instant of ground contact was used to test the feasibility of external airbags for mitigating ground contact. Substantial head and pelvis injury reductions may be possible through the application of controlled braking. Full vehicle braking after first vehicle-pedestrian contact has little influence on overall pedestrian injury outcome. In controlled braking, an external semi-elliptic airbag with a range 2 m can prevent 83.1% ground contact (only 46.6% in actual cases) and there is a high probability (50%) that the available space to control braking is limited if the vehicle deviates from its original lane. Various kinematic explanations are presented, consistent with the principle that the vertical component of the impact on the ground can be reduced by controlling the vehicle braking. Despite the variation in real-world pedestrian collisions, controlled braking may generally provide a benefit for ground contact injuries.

摘要

行人因与地面接触而受到严重伤害，但减少这些伤害的尝试受到了限制。最近一项使用多体模拟的研究表明，通过控制车辆制动可以改善地面接触伤害。该研究的目的是评估受控制动是否有利于现实世界的碰撞。PC-Crash 用于重建 150 个免费可用的真实世界车辆行人视频碰撞。然后对每种情况进行实际制动与受控制动的成对比较。行人伤害评价指标包括头部伤害标准HIC15和骨盆接触力，另一个指标是接触地面时车辆与行人的分离距离，用于测试外部安全气囊减轻地面接触的可行性。通过应用受控制动，可以显着减少头部和骨盆损伤。首次车辆与行人接触后的全车制动对整体行人伤害结果影响不大。在控制制动中，一个射程为 2 m 的外部半椭圆形安全气囊可以防止 83.1% 的地面接触（实际情况下仅为 46.6%），如果控制制动的可用空间有限，则很有可能（50%）。车辆偏离原车道。提出了各种运动学解释，这与通过控制车辆制动可以减少对地面冲击的垂直分量的原理相一致。尽管现实世界中的行人碰撞存在差异，但受控制动通常可以为地面接触伤害提供好处。